Novel Spot-On Active Substance Formulation

ABSTRACT

The invention relates to an improved composition for the control of parasites on animals, comprising comparably high amounts of active substances from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids) and from pyrethroids in a new and improved formulation comprising carvacrol as a solvent, and optionally additionally further active and/or auxiliary substances. In particular, the invention relates to the use of such compositions for the control of ectoparasites such as, in particular, fleas, ticks and sand flies in pets such as, in particular, in dogs and ferrets.

The invention relates to an improved composition for the control of parasites on animals, comprising comparably high amounts of active substances from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids) and from pyrethroids in a new and improved formulation comprising carvacrol as a solvent, and optionally additionally further active and/or auxiliary substances. In particular, the invention relates to the use of such compositions for the control of ectoparasites such as, in particular, fleas, ticks and sand flies in pets such as, in particular, in dogs and ferrets.

INTRODUCTION

Compositions for the control of parasites such as, in particular, ectoparasites, which are based on a combination of active substances from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids) and from pyrethroids are known from the prior art. The disadvantage of spot-on formulations on the basis of permethrin alone is the low activity against fleas. Spot-on formulations based on agonists or antagonists of nicotinic acetylcholine receptors alone are highly active against fleas but have the disadvantage that they are ineffective against ticks. It has been described that insecticidal compositions on the basis of a combination of neonicotinoids and pyrethroids requires the use of relatively large amounts of the active compounds to act effectively against parasitic insects such as ticks and fleas on animals. However, such compositions with high amounts of the active substances are known to cause undesired side-effects such as skin irritations.

Especially the international application WO 2004/064522 with its corresponding US 2006/211655 relates to arthropod-repelling agents, comprising a combination of a pyrethrin or pyrethroid with an agonist of the nicotinergic acetylcholine receptors of arthropods (neonicotinoids). Therein, examples of suitable pyrethroids comprise permethrin, which may be present in an amount of 15 to 75 wt.-%. Examples of neonicotinoids comprise imidacloprid, which may be present in amount of 1 to 25 wt.-%.

Further, the patent family of WO 2002/087338 with its equivalents DE 101 17 676 and U.S. Pat. No. 7,728,011 relates to a dermally applicable liquid formulation comprising a combination of 35 to 60 wt.-% permethrin (pyrethroids) and 2.5 to 12.5 wt.-% imidacloprid (neonicotinoid) in a formulation on the basis of N-methylpyrrolidone (NMP) as the solvent, which is present in amounts between 27.5 to 62.5 wt. %.

Further, WO 2014/131786 relates to veterinary compositions for dermal application comprising a combination of imidacloprid and permethrin in a formulation on the basis of Dimethyl sulfoxide (DMSO) as the solvent, which is present in amounts between 20 to 60 wt. %.

Further compositions comprising neonicotinoids and pyrethroids are known for example from the international application WO 2004/098290, which relates to a combination of a pyrethrin or a pyrethroid with neonicotinoids agents for controlling parasites on animals, wherein the preferred pyrethroid is flumethrin (a so-called type II pyrethroid) which may be combined with the neonicotinoid imidacloprid. Therein it is mentioned that the compositions may comprise the pyrethroids in an amount up to 20 wt.-%, however the specific formulations in the examples comprise less than 1 wt.-% of the pyrethroid compound.

WO 2002/43494 relates to a composition for combating parasites on animals, comprising a combination of a neonicotinoid and a pyrethroid as the active ingredients. The formulations may comprise solvents, which may be selected amongst others from cyclic carbonates and benzyl alcohol.

DE 198 07 633 relates to similar formulations for combating parasites on animals comprising a neonicotinoid alone as the active ingredient.

The problem arising from compositions with high amounts of active substances are the poor solubility of the actives, which are not readily dissolvable in any solvent or solvent formulation.

Imidacloprid is a protic active substance, whereas pyrethroids, such as in particular permethrin, are strongly aprotic compounds, which leads to the difficulty of finding a suitable solvent system for dissolving both components in high amounts and thus provide a homogenous and stable dermally applicable liquid formulation. A further difficulty arises from the tendency of the active substances to recrystallize and precipitate at room temperature and in particular at temperatures below room temperature. For preparing active substance compositions in the form of dermally applicable liquid formulations, it is thus necessary to prepare homogenous solutions or emulsions based on organic solvents. To achieve sufficient and stable dissolution of such high amounts of the active substances, in particular of imidacloprid and permethrin, so far high amounts of N-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO) in amounts of at least 27.5 or 20 wt.-%, respectively, have been required.

However, N-methylpyrrolidone is on the list of Chemicals Known to the State to Cause Cancer or Reproductive Toxicity, cited in California Proposition 65 (1986). Although, DMSO is considered as non-toxic, it has the unusual and undesired property that many individuals perceive a, unpleasing, garlic-like taste in the mouth and exhibit an undesired negative odor due to the sulphur component after contact with the skin. Further both, N-methylpyrrolidone and dimethyl sulfoxide are known to be less compatible and to cause undesired side-effects on the treated animals, such as e.g. the ability of DMSO to harm the eye. The most commonly reported side effects of NMP and DMSO include headaches and burning and itching on contact with the skin. Strong allergic reactions have also been reported. Further both, N-methylpyrrolidone and dimethyl sulfoxide are known to support transdermal passage of active substances. Therewith the active substances become partially systemic available and are topically no longer available. This reduces the efficacy of the topically active agents and is undesired in particular in spot-on or pour-on formulations.

In principle, alternative solvent formulations for active substance compositions, comprising combinations of neonicotinoids with pyrethroids have been described.

For example, the international application WO 2001/35739 relates to active substance compositions, comprising combinations of neonicotinoids such as imidacloprid with pyrethroids such as flumethrin using polysiloxanes containing quaternary amino groups as the auxiliary agents of the active substance formulations. Therein the active substances are present only in comparably small amounts.

The international application WO 2013/000572 with its corresponding US 2015/0038537 relates to a combination of an active substance from the group of pyrethroids such as deltamethrin or flumethrin (both so-called type II pyrethroids) with an active substance from the group of phenylpyrazoles such as fipronil. Therein a formulation comprising a propylene carbonate and benzylalcohol is mentioned. However, the application remains silent about a combination with a neonicotinoid and further relates to comparably small amounts of the pyrethroid of not more than 7 wt.-%.

The international application WO 2008/080542 and its priority application DE 10 2006 061538 relates to agents for controlling parasites on animals, comprising a combination of N-arylpyrazoles and pyrethroids in a formulation containing aliphatic cyclic carbonates and aliphatic cyclic or acyclic polyethers. Therein, a comparative example 3 is mentioned, comprising a combination of imidacloprid with the type II pyrethroid flumethrin in a small amount of less than 1 wt.-%.

WO2014/140314 relates to compositions for repelling insects or arachnids by using carvacrol, cumin and cinnamate compounds as the active repellent agent. Further known insecticides are generally mentioned in a list of possible mixing partners, comprising amongst others also permethrin and imidacloprid. A specific combination of imidacloprid and permethrin and the particular suitability of carvacrol as a solvent for said specific insecticide combination, in particular when present in comparably high amounts, is not disclosed therein.

OBJECT

It was the object of the present invention to find an alternative solvent or formulation for a highly effective active substance combination, particularly with a high level of long-term action, with high amounts of a neonicotinoid and a pyrethroid, such as preferably imidacloprid and permethrin, which avoids the aforementioned disadvantages. It was particularly desired to provide an alternative formulation for such highly concentrated active substance combination, which exhibits low toxic potential and causes less or even no undesired side-effects, in particular exhibits a high level of compatibility, particularly skin compatibility, and good applicability with low skin penetration (since the action of the active compounds should preferably be non-systemic). When searching for a solution for improving the compatibility of so far known active ingredient formulations, the inventors of the present invention have also considered to exchange NMP with its undesired toxic side-effects against DMSO, which is also a known and widely-used solvent. However, DMSO exhibits similar tissue penetration effects as NMP, thereby reducing the availability and efficacy of the topically applied actives by subcutaneous transport. Such effect is particularly not desired, and it was thus a further object of the present invention to develop a novel and improved active ingredient formulation for said specific active ingredient combination, which does not have the disadvantages of the known active ingredient formulations on the basis of NMP and DMSO, such as in particular the tissue penetration effects. At the same time the novel formulation should provide good solubility of the high amounts of active substances and thus allow the preparation of a homogeneously dissolved active substance composition with high stability (in particular storage-stability) in all climate zones. The novel compositions should particularly be suitable as spot-on or pour-on formulations.

DETAILED DESCRIPTION OF THE INVENTION

The inventors of the present invention surprisingly found that the aforementioned disadvantages can be solved by providing a composition for the control of parasites on animals, which comprises

-   -   at least one active substance selected from the group of         agonists of the nicotinergic acetylcholine receptors of insects         (neonicotinoids);     -   at least one active substance, selected from the group of         pyrethroids; and     -   ≥8.0 wt.-%, based on the weight of the total composition, of         carvacrol as a solvent; as well as     -   optionally, at least one crystallization inhibitor;     -   optionally at least one further active substance from the group         of development inhibitors; and/or     -   optionally additionally further solvents and/or active         substances and/or auxiliary substances.

The group of agonists of the nicotinergic acetylcholine receptors of insects in the sense of the present invention preferably refers to neonicotinoids. Neonicotinoids are known for example from US 2006/0211655, U.S. Pat. No. 7,728,011 and from the prior art as mentioned therein. Examples comprise acetamiprid, clothianidin, dinotefuran, imidacloprid (also comprising imidacloprid analogues), nitenpyram, thiacloprid, and thiamethoxam, with imidacloprid (including imidacloprid analogues) being particularly preferred.

Imidacloprid ((E)-1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine or (2E)-1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidin-imine) is a synthetic insecticide having the structural formula

It acts as an insect neurotoxin and belongs to the class of neonicotinoids, which act on the central nervous system of insects by interfering with the transmission of stimuli in the insect nervous system. Specifically, it causes a blockage in the nicotinergic neuronal pathway, namely a blockage of the nicotinic acetylcholine receptors, thus preventing acetylcholine from transmitting impulses between nerves, resulting in the insect's paralysis, and even in its death. Imidacloprid is effective on contact and via stomach action.

Pyrethroids in the sense of the present invention are known for example from US 2006/0211655 and from the prior art as mentioned therein.

Within the context of the present invention, active substances from the group of the pyrethroids include both natural as well as synthetic pyrethroids. Natural pyrethroids include, in particular, pyrethrins, such as pyrethrin I and pyrethrin II as well as extracts thereof, as well as pyrethrum and derivatives thereof.

Synthetic pyrethroids may be classified as the so-called type I pyrethroids (without alpha-cyano group), type II pyrethroids (alpha-cyano pyrethroids with alpha-cyano group) and non-ester pyrethroids. They differ from one another substantially with regard to their acute actions.

In animal testing, type I pyrethroids lead to side effects such as the so-called “T-syndrome”, which is named after the tremor that occurred in the test animals. Ataxia, hyper excitability and hypersensitivity to stimuli are also observed in the case of the “T syndrome”. Examples of type I pyrethroids comprise allethrin, bioallethrin, barthrin, cyclethrin, dimethrin, permethrin (indothrin), biopermethrin, phenothrin (sumithrin), resmethrin (cismethrin), bioresmethrin tetramethrin (phthalthrin) and transfluthrin.

Type II pyrethroids cause as a side effect the so-called “CS syndrome” which is named after the characteristic symptoms choreoathetosis (involuntary slow movements) and salivation that occurred in the test animals. In addition, a coarse tremor and clonic spasms also occur in this case. Examples of type II pyrethroids comprise alpha-cypermethrin, cyfluthrin, beta-cyfluthrin, cyhalothrin, cypermethrin, cyphenothrin, deltamethrin, fenpropanate, fenvalerate, flucythrinate, flumethrin, fluvalinate (tau-fluvalinate), tralomethrin and tralocythrin.

Examples of non-ester pyrethroids comprise, for example, etofenprox, halfenprox and silafluofen.

According to the present invention type I pyrethroids are preferred. Particularly preferred is permethrin.

Permethrin (3-phenoxybenzyl (1RS,3RS; 1RS,3SR)-3-(2,2-dichloro-vinyl)-2,2-dimethylcyclopropanecarboxylate or (3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate) is a synthetic insecticide, acaricide, and insect and acarid repellent having the structural formula

It functions as a neurotoxin, affecting neuron membranes by prolonging sodium channel activation and acts against a broad spectrum by contact and stomach action. It exhibits a repellant effect.

Accordingly the composition of the present invention preferably comprises a combination of imidacloprid, as an active substance from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids), and permethrin, as an active substance from the group of the pyrethroids.

The compositions of the present invention may optionally comprise at least one further active substance, which may preferably be selected from the group of the so-called development inhibitors or insect growth regulators.

Development inhibitors or insect growth regulators regulate the development of insect larvae and prevent their further development and growth into an adult pest, and thus their reproduction. Development inhibitors may come, for example, from the group of the juvenile hormones. Development inhibitors and insect growth regulators include, for example, juvenile hormones, such as azadirachtin, diofenolan, fenoxycarb, hydroprene, kinoprene, methoprene, pyriproxyfen, tetrahydroazadirachtin, 4-chloro-2-(2-chloro-2-methylpropyl)-5-(6-iodo-3-pyridylmethoxy)pyridizin-3(2h)-one; as well as chitin synthesis inhibitors, such as chlorofluazuron, cyromazine, diflubenzuron, fluazuron, flucycloxuron, flufenoxuron, hexaflumuron, lufenuron, tebufenozide, teflubenzuron, triflumuron. Pyriproxyfen and methoprene are preferred development inhibitors, particularly preferred is pyriproxyfen.

All of the active substances mentioned within the context of the invention can additionally be defined by the internationally known designations according to “The Pesticide Manual”; 10th edition, 1994, Ed. Clive Tomlin, Great Britain.

If applicable, the active substances used according to the invention can be present, depending on the type and arrangement of the substituents, in various stereo isomeric forms, particularly as enantiomers and race mates, wherein both the pure stereoisomers as well as mixtures thereof can be used according to the invention.

Optionally, the active substances according to the invention can also be used in the form of their salts, with pharmaceutically suitable acid addition salts and basic salts being eligible, such as, for example, salts of mineral acids or organic acids (for example carboxylic acids or sulphonic acids), such as, in particular, hydrochloric acid, sulphuric acid, acetic acid, glycolic acid, lactic acid, succinic acid, citric acid, tartaric acid, methanesulphonic acid, 4-toluenesulphonic acid, galacturonic acid, gluconic acid, embonic acid, glutamic acid or aspartic acid. Pharmaceutically suitable basic salts include, for example, alkali metal salts, such as sodium or potassium salts, and alkaline earth metal salts, such as magnesium or calcium salts.

The active substances according to the invention can also be used in the form of their solvates, in particular hydrates, which includes both the solvates (in particular hydrates) of the active substances themselves as well as those of their salts.

The amounts of the active substances in the composition of the present invention may be varied broadly. Indicated amounts (e.g. in wt.-%) relate to the total weight of the composition.

According to the present invention the active substance from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids), such as in particular imidacloprid, may vary between about 2.5 to 12.5 wt.-%, preferably between about 5.0 to 10.0 wt.-%, more preferably between about 6.5 to 10.0 wt.-%.

According to the present invention the active substance from the group of pyrethroids, in particular type I pyrethroids such as in particular permethrin, may vary between about 30.0 to 60.0 wt.-%, preferably between about 32.0 to 60.0 wt.-%, more preferably between about 34.0 to 55.0 wt.-%.

Accordingly, a further aspect of the present invention relates to a composition as described herein, comprising from about 2.5 to 12.5 wt.-% of at least one active substance selected from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids), such as preferably imidacloprid, and from about 30.0 to 60.0 wt.-% of at least one active substance selected from the group of pyrethroids, such as preferably permethrin, with the amounts being based on the weight of the total composition.

A further aspect of the present invention relates to a composition as described herein, comprising from about 5.0 to 10.0 wt.-%, preferably about 6.5 to 10.0 wt.-% of the active substance from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids), such as preferably imidacloprid, and from about 32.0 to 60.0 wt.-%, preferably about 34.0 to 55.0 wt.-% the active substance from the group of the pyrethroids, such as preferably permethrin, with the amounts being based on the weight of the total composition.

In a preferred embodiment the composition of the present invention comprises the active substances from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids), such as in particular imidacloprid, and from the group of the pyrethroids, such as in particular a type I pyrethroid, particularly permethrin, in a total amount (sum) of at least 32.5 to 72.5 wt.-%, at least 37.0 to 70.0 wt.-%, at least 40.5 to 65.0 wt.-%, or at least 40.0 to 60.0 wt.-%.

In a further preferred embodiment the composition according to the present invention comprises the active substances from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids), such as in particular imidacloprid, and from the group of the pyrethroids, such as in particular a type I pyrethroid, particularly permethrin, in a (weight-) ratio of about 1:5.

As already mentioned above, in particular active substances from the group of the pyrethroids, such as inter alia permethrin, are known for their irritating effect on the skin and the mucosa and for the occurrence of side effects in the form of skin-incompatibility reactions, such as pruritus (itching), burning, pricking, erythema development and reddening, edema development and allergic reactions. In addition the occurrence of paresthesias has been described in connection with the application of pyrethroids, in particular with the application of type II pyrethroids (cyano-pyrethroids).

Further, undesired side-effects such as general symptoms of poisoning, headache, nausea, dizziness as well as disorders of the central nervous system, functional disorders of the liver and kidneys and blood count disorders can arise from the commonly used solvent N-methylpyrrolidone and DMSO. It is therefore preferred that the compositions of the present invention contain at a maximum equal to or less than (≤) 20.0 wt.-% N-methylpyrrolidone and/or DMSO, ≤10.0 wt.-% N-methylpyrrolidone and/or DMSO, preferably ≤ or ≤9.0 wt.-% N-methylpyrrolidone and/or DSMO, such as in particular 0 to 10.0 wt.-% or 0 to 9.0 wt.-% N-methylpyrrolidone and/or DMSO. In a very particularly preferred embodiment the compositions of the present invention are essentially free of N-methylpyrrolidone and DMSO.

However, as mentioned above, N-methylpyrrolidone has so far been required to sufficiently dissolve the high amounts of effective insecticidal combination products on the basis of e.g. imidacloprid and permethrin.

The inventors of the present invention have now surprisingly found that the use of carvacrol as a solvent provides sufficient dissolution even of high amounts of the active substances according to the present invention. The composition of the present invention preferably comprises the solvent carvacrol in an amount of ≥(equal or more than) 8.0 wt.-%, based on the weight of the total composition. More preferably, the composition of the present invention comprised the solvent carvacrol in an amount of ≥about 10.0 wt. % (preferably ≥(more than) 10.0 wt. %), ≥about 15.0 wt. %, ≥about 20.0 wt. %, ≥about 25.0 wt. %, ≥about 30.0 wt. %, ≥about 35.0 wt. %, ≥about 40.0 wt. %, in each case based the weight of the total composition.

The particular suitability of carvacrol as a solvent for solubilizing comparably high amounts of the actives according to the present invention was in so far surprising, as carvacrol is mainly mentioned in context with inhibiting growth of several bacteria strains or as a repellent per se. Further its pleasant taste and smell suggests it as a food additive with anti-bacterial effect. Carvacrol, also designated as iso-thymol or thymol stereoisomer (5-isopropyl-2-methylphenol or 2-Methyl-5-(1-methylethyl)-phenol), is a naturally occurring monoterpenoid phenol compound and a stereoisomer of the natural phenolic compound thymol:

Carvacrol (as well as thymol) is present in the essential oil of Origanum vulgare (oregano), in the oil of thyme, in oil obtained from pepperwort and from wild bergamot. Surprisingly, the advantageous solubilizing effects in the formulations of the present invention could not equally be observed with thymol, but only with the stereoisomer carvacrol.

In a further aspect of the invention a solvent formulation comprising a mixture of carvacrol with at least one additional solvent which is selected from the group consisting of cyclic carbonate, such as preferably propylene carbonate, and aromatic alcohol, such as preferably benzyl alcohol, may be used. In a further aspect of the invention a solvent formulation comprising a mixture of carvacrol with both, a cyclic carbonate, such as preferably propylene carbonate, and an aromatic alcohol, such as preferably benzyl alcohol may be used.

Aliphatic cyclic carbonates in accordance with the present invention are also called carbonate ester, i.e. ester of carbonic acid and comprise for example ethylene carbonate, propylene carbonate and mixtures thereof, with propylene carbonate being preferred.

Aromatic alcohols comprise for example benzyl alcohol, phenylethanol, phenoxyethanol and mixtures thereof, with benzyl alcohol being preferred.

Accordingly it is particularly preferred to use a solvent mixture comprising propylene carbonate and benzylalcohol.

The amounts of the aliphatic cyclic carbonate and the aromatic alcohol in the composition of the present invention may be varied broadly. Indicated amounts (e.g. in wt.-%) relate to the total weight of the composition.

According to the present invention the aliphatic cyclic carbonate, such as in particular propylene carbonate, may vary between about 8.0 to 48.0 wt.-%, preferably between about 9.0 to 40.0 wt.-%. In a further preferred embodiment the propylene carbonate may vary between about 20.0 to 40.0 wt.-%.

In one aspect of the invention a solvent formulation may be used, comprising ≤(equal or less than) about 50.0 wt.-%, or ≤about 40.0 wt.-%, or ≤about 30.0 wt.-%, or ≤about 20.0 wt.-% of the at least one aliphatic cyclic carbonat, such as preferably propylene carbonate.

According to the present invention the aromatic alcohol, such as in particular benzyl alcohol, may vary between about 9 to 40 wt.-%, preferably between about 9 to 30 wt.-%.

In one aspect of the invention a solvent formulation may be used, comprising ≤(equal of less than) about 20.0 wt. %, or ≤about 15.0 wt. %, or ≤about 10.0 wt. % of the at least one aromatic alcohol, such as in particular benzyl alcohol.**

According to the invention, any of the aforementioned ranges of the aliphatic cyclic carbonate may be combined with any of the aforementioned ranges of the aromatic alcohol.

In a further aspect of the invention a solvent formulation may be used, comprising at least one cyclic carbonate, such as in particular propylene carbonate, and at least one aromatic alcohol, such as in particular benzyl alcohol, which are present in a ratio of about 1:6 to 6:1, preferably about 1:5 to 5:1, about 1:4 to 4:1, about 1:3 to 3:1, about 1:2.5 to 2.5:1, about 1:2 to 2:1, about 1:1.5 to 1.5:1, about 1:1.2 to 1.2:1, or about 1:1.

In a further possible embodiment the amount of aliphatic cyclic carbonate, such as in particular propylene carbonate, exceeds the amount of the aromatic alcohol, such as in particular benzyl alcohol or is at least substantially equal, resulting in preferred ratios of aliphatic cyclic carbonate:aromatic alcohol of about 6:1, preferably about 5:1, preferably about 4:1, about 3:1, about 2.5:1, about 2:1, about 1.5:1, about 1.2:1, or about 1:1.

Therein, the term “substantially equal” or “about” means to include a variance of ±5%.

The compositions of the present invention may further comprise at least one crystallization inhibitor. The addition thereof may be advantageous with respect to the further improvement of the solubility and stability of the formulations. Upon addition of a crystallization inhibitor the tendency of the active substances to crystallize and precipitate, for example at room temperature and even at temperatures below room temperatures such as in a refrigerator, can further be positively influenced and it may become possible to further improve the stability and homogeneity of the compositions of the present invention by adding a crystallization inhibitor.

According to the invention the group of crystallization inhibitors comprises for example glycerine, propylene glycol, mineral oils, silicon oils, vegetable oils, e.g. olive oil, rapeseed oil, soy bean oil, sunflower oil, cottonseed oil, peanut oil, lin seed oil, rice bran oils etc.

Preferred crystallization inhibitors are glycerine and propylene glycol as well as one or more vegetable oils, with glycerine being particularly preferred.

The combination of carvacrol with glycerine, propylene glycol or a vegetable oil as a crystallization inhibitor turned out to be very effective in further increasing the solubility, stability and homogeneity of the high concentrated active ingredient formulations of the present invention.

By selecting carvacrol as a new solvent in a new formulation for the selected active substance combination as defined above, it was surprisingly possible to provide a new active substance formulation which is not only highly effective in controlling parasites on animals, but which is particularly characterized by a remarkably improved compatibility, reduced undesired side-effects, such as mentioned above, reduced toxicity, improved applicability when applied topically (dermal, external application) and which is even improved with respect to its efficacy compared to common formulations with high amounts of N-methylpyrrolidone or DMSO, as the effect of transdermal active substance transport, effected e.g. by the NMP and DMSO, is reduced or even totally avoided.

The compositions of the present invention may optionally additionally comprise further active and/or auxiliary substances.

Suitable auxiliary substances are customary auxiliary substances, such as, for example, (additional) solvents, spreading agents, solubilizer, emulsifier, synergists for the active substances according to the invention, antioxidants, preservatives, stabilizers, pH-adjusting agents, thickeners, fillers, adherents, crystallization inhibitors (other than those listed above), colorants, fragrances etc. Some compounds exhibit more than one auxiliary effect and may thus be classified in several groups of mentioned auxiliaries. Accordingly, some compounds may be mentioned in different groups.

Spreading agents or solubilizer include, for example, surface active agents, such as surfactants, such as anionic surfactants (e.g. sodium laurylsulfate, fatty alcohol ether sulfates and monoethanolamine salts of mono-/di-alkylpolyglycolether orthophosphoric acid esters), cationic surfactants (e.g. cetyl trimethyl ammonium chloride) amphoteric surfactants (e.g. di-sodium-N-laurylaminodipropionate or lecithin), and non-ionic surfactants (e.g. polyoxyethylated castor oil, polyoxyethylated sorbitane monooleate, ethylalcohol, glycerol monosterate, polyoxyethylene stearate and alkylphenol polyglycol ether) as well as, in particular, polymeric surfactants, for example those based on polymethoxysiloxanes, silicones, fats and oils, such as, for example, silicone oils of different viscosities; fatty acid esters such as ethylstearate, di-n-butylester, lauric acid hexylester, dipropylene glycol pelargonate, esters of a branched fatty acid with a medium chain length and saturated C₁₆-C₁₈ fatty alcohols, isopropyl myristate, isopropyl palmitate, caprylic/capric acid esters from saturated fatty alcohols with a chain length of C₁₂-C₁₈, isopropyl stearate, oleic acid oleyl ester, oleic acid decyl ester, ethyloleate, sorbitan esters (Spans), such as sorbitan monolaurate (Span 20), sorbitan monooleate (Span 80), sorbitan monopalmitat (Span 40) or sorbitan tristearate (Span 65), lactic acid ethyl ester, wax-like fatty acid esters, dibutyl phthalate, adipic acid diisopropyl esters and ester mixtures; triglycerides based on oleic acid, palmitic acid, linoleic acid, stearic acid, caprylic acid and capric acid, such as in particular caprylic/capric acid triglyceride, triglyceride mixtures with vegetable fatty acids with a chain length of C₈-C₁₂ or other especially selected natural fatty acids, partial glyceride mixtures of saturated and unsaturated fatty acids and mono and/or diglycerides of the C₈-/C₁₀-fatty acids; fatty alcohols, such as isotridecyl alcohol, 2-octyldodecanol, cetylstearyl alcohol and oleyl alcohol; fatty acids, such as oleic acid, palmitic acid, linoleic acid, stearic acid, caprylic acid and capric acid, lactones, such as butyrolactone; phospholipids and phosphatidylcholines etc. Fatty acid esters and sorbitan esters are particularly preferred spreading agents or solubilizer, with isopropyl myristate and sorbitan monolaurate (Span 20) being selected with particular preference.

Possible (additional) solvents include, for example, water, pyrrolidones, such as pyrrolidone-2, N-methylpyrrolidone, N-octyl-, N-butylpyrrolidone, low-boiling alcohols, such as isopropanol, ethanol, higher alcohols, such as n-octyl alcohol, lanolin alcohol and n-butanol, cyclic and acyclic ketones, such as acetone, methyl ethyl ketone and cyclohexanone, glycols, such as ethylene glycol and propylene glycol, aliphatic cyclic or acyclic ethers, such as tetrahydrofurfuryl alcohol, diethylene glycol monoethyl ether, dipropylene glycol monopropyl ether and glycofurol, benzyl benzoate, vegetable or synthetic oils, dimethylformamide (DMF), and glycerine etc.

Antioxidants and stabilizers which may be mentioned are sulphites or metabisulphites, such as potassium metabisulphite; organic acids, such as citric acid, ascorbic acid, malic acid; phenols, butylhydroxytoluene (BHT), butylhydroxyanisole, vitamin E (tocopherols) and derivatives thereof, etc., vitamin E (tocopherols) and its derivatives and butylhydroxytoluene (BHT) being preferred antioxidants.

The amounts of antioxidant may be varied broadly in the range of 0 to 1.0 wt.-%, preferably 0 to 0.5 wt.-%, preferably the amounts of antioxidants are in the range of 0.05 to 0.25 wt-%, more preferably in the range of 0.05 to 0.15 wt.-%.

However, vitamin E and its derivatives may be used in even higher amounts such as in a quantity of 0 to ≥20.0 wt.-%. Preferably, vitamin E or its derivatives is used in amounts ≥3 wt.-% preferably ≥5.0 wt.-%, preferably ≥7.0 wt.-%, preferably ≥10.0 wt.-%. Moreover, it is further preferred to use vitamin E or its derivatives in an amount of ≥12.0 wt.-%, more preferably ≥15.0 wt.-%, more preferably ≥18.0 wt.-%, still more preferably ≥20.0 wt.-%.

Therein and within the context of the present invention, vitamin E derivatives in particular relate to glycosides, esters, salts and complexes of vitamin E. Esters of vitamin E include for example vitamin E nicotinate and vitamin E acetate (or tocopherol nicotinate or acetate or tocopheryl nicotinate or acetate, respectively). Therein, vitamin E acetate is particularly preferred.

The addition of vitamin E or its derivatives, in particular in the comparably high amounts as defined herein, is preferred with respect to the findings as described in US 2015/038537, wherein it has been shown that side effects and incompatibility reactions, which can be caused by the application or the dermal (topical, external) contact with active substances from the group of pyrethroids, can be reduced or suppressed by the simultaneous administration of vitamin E, particularly vitamin E acetate (tocopheryl acetate), in particular in the comparably high amounts as defined herein. In particular, topical or dermal side effects, such as pruritus (itching) and erythema development (reddening) as well as alopecia and also an increased salivation of the mucosa can be reduced by means of the combination of the pyrethroids with vitamin E (vitamin E acetate) according to the invention. Further, paresthesias can be reduced or suppressed. In particular, the immediate (concurrent, simultaneous) administration of the insecticidal active substances with vitamin E or vitamin E acetate in a combination preparation is preferred in the sense of a prophylactic treatment.

Colorants are all colorants approved for use on animals and which can be dissolved or suspended.

Adherents, filler and thickener are, for example, cellulose derivatives, such as carboxymethylcellulose, methylcellulose and other cellulose, starch derivatives, polyacrylates, natural polymers such as alginates, gum arabic, gelatin, polyvinylpyrrolidone, polyvinyl alcohol, copolymers of methyl vinyl ether and maleic anhydride, polyethylene glycols, waxes, colloidal silica, etc.

Emulsifier which may be mentioned are, for example, nonionic surfactants, e.g. polyethoxylated castor oil, polyethoxylated sorbitan monooleate, glycerol monostearate, polyoxyethyl stearate, alkylphenyl polyglycol ethers, etc.; ampholytic surfactants such as disodium N-lauryl-[beta]-iminodipropionate or lecithin; anionic surfactants, such as sodium lauryl sulphate, fatty alcohol ether sulphates, mono/dialkyl polyglycol ether orthophosphate monoethanolamine salt; cationic surfactants such as cetyltrimethylammonium chloride.

It is certainly possible to use mixtures of more than one of the aforementioned substances in the compositions of the present invention.

The compositions according to the invention are environmentally compatible and user-friendly due to the very low level of toxicity.

In a preferred embodiment the composition of the invention comprises at least one additional active and/or auxiliary substance, which is selected from the group consisting of antioxidants, such as butylated hydroxytoluene (BHT), vitamin E or derivatives thereof, at least one crystallization inhibitor, such as glycerine, propylene glycol and/or at least one vegetable oil, organic solvents and water.

The compositions according to the invention are suitable for the control of parasitic insects that occur in the keeping and breeding of animals in pets and useful animals, as well as in zoo animals, laboratory animals, test animals and hobby animals. They are effective particularly against parasitic pests selected from the group of the ectoparasites, such as insects and mites (e.g. lice, flies, fleas, sand flies, mosquitos, ticks, mites, etc.), in particular including, for example:

from the order of the Anoplura, for example, Haematopinus spp., Linognathus spp., Solenopotes spp., Pediculus spp., Pthirus spp.;

from the order of the Mallophaga, for example, Trimenopon spp., Menopon spp., Eomenacanthus spp., Menacanthus spp., Trichodectes spp., Felicola spp., Damalinea spp., Bovicola spp;

from the order of the Diptera, suborder Brachycera, for example, Chrysops spp., Tabanus spp., Musca spp., Hydrotaea spp., Muscina spp., Haematobosca spp., Haematobia spp., Stomoxys spp., Fannia spp., Glossina spp., Lucilia spp., Calliphora spp., Auchmeromyia spp., Cordylobia spp., Cochliomyia spp., Crysomyia spp., Sarcophaga spp., Wohlfartia spp., Gasterophilus spp., Oesteromyia spp., Oedemagena spp., Hypoderma spp., Oestrus spp., Rhinoestrus spp., Melophagus spp., Hippobosca spp;

from the order of the Diptera, suborder Nematocera, for example, Culex spp., Aedes spp., Anopheles spp., Culicoides spp., Phlebotomus spp., Simulium spp.;

from the order of the Siphonaptera, for example, Ctenocephalides spp., Echidnophaga spp., Ceratophyllus spp., Pulex spp.;

from the order of the Metastigmata, for example, Hyalomma spp., Rhipicephalus spp., Boophilus spp., Amblyomma spp., Haemaphysalis spp., Dermacentor spp., Ixodes spp., Argas spp., Ornithodorus spp., Otobius spp.;

from the order of the Mesostigmata, for example Dermanyssus spp., Ornithonyssus spp., Pneumonyssus spp.;

from the order of the Prostigmata, for example Cheyletiella spp., Psorergates spp., Myobia spp., Demodex spp., Neotrombicula spp.;

from the order of the Astigmata, for example, Acarus spp., Myocoptes spp., Psoroptes spp., Chorioptes spp., Otodectes spp., Sarcoptes spp., Notoedres spp., Knemidocoptes spp., Neoknemidocoptes spp., Cytodites spp., Laminosioptes spp.

Particularly preferred, according to the invention, is the control of parasitic insects from the group of the ectoparasites, such as, in particular, lice, ticks, fleas, mosquitos and sand flies.

Accordingly, a preferred embodiment relates to compositions according to the present invention for use in the prophylactic or acute treatment against ectoparasites, in particular against lice, ticks, fleas, mosquitos and sand flies.

Within the context of the present invention, the term useful and breeding animals includes, for example, cattle, horses, sheep, pigs, goats, camels, water buffalo, donkeys, rabbits, fallow deer, reindeer, fur-bearing animals, such as, for example, mink, chinchilla, racoon, birds, such as, for example, hens, geese, turkeys, ducks, etc.

According to the invention, the term hobby animals and pets, as well as laboratory and test animals includes, for example, mice, rats, guinea pigs, golden hamsters, dogs and ferrets as well as hedgehogs.

Accordingly, a particular aspect relates to the composition of the present invention for the use in the prophylactic and/or acute treatment of hobby animals, pets, laboratory and test animals, such as preferably mice, rats, guinea pigs, golden hamsters, dogs and ferrets and hedgehogs.

Preferably, the compositions according to the invention are provided for use in the treatment of dogs and ferrets.

In this case, application can take place both prophylactically and therapeutically, or for acute treatment.

Accordingly, another preferred embodiment relates to compositions according to the present invention for use in the prophylactic or acute treatment of dogs and ferrets.

According to the invention, application on the animal takes place directly or preferably in the form of suitable preparations, such as, in particular, the active substance formulations according to the invention.

A skin contact that is as good and extensive as possible is in this case advantageous for optimal action, in particular the repellent action of the pyrethroid active substances.

The use of the compositions according to the invention for the external, topical or dermal use is particularly preferred.

Suitable preparations therefore are solutions or concentrates for administration after dilution for use on the skin or in body cavities, infusion formulations, gels, emulsions and suspensions, semi-solid preparations, such as formulations in which the active substance is processed in an ointment base or in an oil-in-water or water-in-oil emulsion base, solid preparations such as powders, premixes or concentrates, granulates, pellets, aerosols and active substance-containing molded bodies, which are used, for example, by dissolving and optionally diluting them for use on the skin etc. According to the invention, application preferably takes place by spraying, pouring, dripping or by application via collars for pets, such as for cats or dogs or ferrets.

In particular, the use as a spot-on or pour-on formulation is preferred according to the invention. Accordingly, the compositions of the present invention are preferably in the form of a spot-on formulation or a pour-on formulation.

The application volumes of the compositions of the present invention preferably vary between 0.075 to 0.25 ml/1.0 kg body weight of the animal treated, preferably 0.1 to 0.15 ml/1.0 kg body weight of the animal treated. Such small applicable volumes are particularly preferred for spot-on formulations, which are preferred according to the invention.

According to the invention, the use of the above-described novel compounds for the control of parasites, such as, in particular, ectoparasites, particularly of ticks, fleas and sand flies, for example by application on and treatment of equipment from the keeping of animals, such as, for example, animal baskets, padding, brushes, cages, stables, etc., is comprised. In this case, the use may also take place both for the prophylactic as well as for the acute treatment.

Accordingly, the invention further relates to a method of controlling ectoparasites, as defined above, on animals, the method comprising topically applying a composition according to the present invention to an animal, as defined above, to be treated. In such method the definitions and preferences as given above apply accordingly.

To prepare the compositions according to the invention, appropriate amounts of the desired components are mixed with one another in accordance with known methods using, for example, conventional stirring tanks or other suitable devices, preferably under heating the mixture prior to and upon mixing.

The invention further particularly relates to the use of carvacrol as a solvent in a composition for the control of parasites on animals, such as in particular as a solvent for the active ingredients as defined herein. Further aspects of said new use further comprise the particular selection of suitable amounts thereof in the active ingredient formulation, specific mixing partners and active ingredient combinations, as well as the specific application fields and administration forms, each as defined herein.

The invention is illustrated in more detail by the following examples. The examples merely constitute exemplifications, and the person skilled in the art is capable of extending the specific examples to other embodiments for which protection is sought.

EXAMPLES 1. Composition Examples (Compositions According to the Invention) Example 1 Spot-on Formulation

weight wt. Ingredient [g] [%] mg/ml Imidacloprid 50 7 80.65 Permethrin 250 34.99 403.23 Pyriproxifen 2.5 0.35 4.03 Propylene carbonate 281.5 39.4 Benzyl alcohol 70 9.8 Glycerin 0.47 0.07 0.76 Carvacrol 60 8.4 total weight [g] 714.47 total volume [ml] 620 storage stability (RT) + + + storage stability refrigerator + + +

Example 2 Spot-on Formulation

weight wt. Ingredient [g] [%] mg/ml Imidacloprid 50 6.99 80.65 Permethrin 250 34.96 403.23 Pyriproxifen 2.5 0.35 4.03 Propylene carbonate 281.5 39.36 Benzyl alcohol 70 9.79 BHT 0.71 0.1 1.15 Glycerin 0.47 0.07 0.76 Carvacrol 60 8.39 total weight [g] 715.18 total volume [ml] 620 storage stability (RT) + + + storage stability refrigerator + + +

Example 3 Spot-on Formulation

weight wt. Ingredient [g] [%] mg/1.2 ml Imidacloprid 50 7.78 102.56 Permethrin 250 38.92 512.82 Pyriproxifen 2.5 0.39 5.13 Propylene carbonate 0.0 0.00 Benzyl alcohol 57.6 8.97 BHT 0.6 0.09 Glycerin 0.5 0.08 Carvacrol 281.2 43.77 total weight [g] 642.4 total volume [ml] 585 storage stability (RT) + + + storage stability refrigerator + +

Example 4 Spot-on Formulation

weight wt. Ingredient [g] [%] mg/1.2 ml Imidacloprid 50 6.98 100.00 Permethrin 250 34.90 500.00 Pyriproxifen 2.5 0.35 5.00 Propylene carbonate 0.0 0.00 Benzyl alcohol 0.0 0.00 BHT 0.6 0.09 Glycerin 0.5 0.08 Carvacrol 341 52.90 total weight [g] 644.6 total volume [ml] 600 storage stability (RT) + + + storage stability refrigerator + +

The preparation of the compositions took place in each case by mixing the individual constituents with one another under slight heating, until a clear, single-phase liquid was obtained.

The Example compositions were stable at room temperature (RT; 20° C.±5° C.) as well as under decreased temperatures in a refrigerator (4 to 6° C.).

The stability of the Example compositions was examined with respect to the dissolution behaviour of the incorporated ingredients, the homogeneity of the prepared solutions, the (undesired) crystallization behavior and the occurance of undesired discoloration.

The Example compositions were ranged with respect to these properties by “+++” (indicating excellent stability), “++” (indicating good stability), “+” (indicating low but still acceptable stability), “−” (indicating low and insufficient stability), “−−” (indicating worse and inacceptable stability) and “−−−” (indicating absolutely unsuitable compositions).

The invention is further defined by the following items.

-   Item 1. A composition for the control of parasites on animals,     comprising     -   at least one active substance selected from the group of         agonists of the nicotinergic acetylcholine receptors of insects         (neonicotinoids);     -   at least one active substance, selected from the group of         pyrethroids; and     -   ≥8.0 wt.-%, based on the weight of the total composition, of         carvacrol as a solvent; as well as     -   optionally at least one crystallization inhibitor;     -   optionally at least one further active substance from the group         of development inhibitors; and/or     -   optionally additionally further solvents and/or active         substances and/or auxiliary substances. -   Item 2. The composition according to item 1, wherein     -   the active substance from the group of agonists of the         nicotinergic acetylcholine receptors of insects (neonicotinoids)         is imidacloprid, and     -   the active substance from the group of the pyrethroids is         permethrin. -   Item 3. The composition according to item 1 or 2, wherein the     solvent carvacrol is present in an amount of ≥10.0 wt. %, preferably     ≥10.0 wt. %, more preferably ≥15.0 wt. %, more preferably ≥20.0 wt.     %, more preferably ≥25.0 wt. %, more preferably ≥30.0 wt. %, more     preferably ≥35.0 wt. %, more preferably ≥40.0 wt. %, based the     weight of the total composition. -   Item 4. The composition according to any one of the preceding items,     comprising     -   from about 2.5 to 12.5 wt.-%, preferably about 5.0 to 10.0         wt.-%, more preferably about 6.5 to 10.0 wt.-% of at least one         active substance selected from the group of agonists of the         nicotinergic acetylcholine receptors of insects         (neonicotinoids), such as preferably imidacloprid; and     -   from about 30.0 to 60.0 wt.-%, preferably about 32.0 to 60.0         wt.-%, more preferably about 34.0 to 55.0 wt.-% of at least one         active substance selected from the group of pyrethroids, such as         preferably permethrin;     -   in each case based the weight of the total composition. -   Item 5. The composition according to any one of the preceding items,     wherein at least one additional active substance from the group of     development inhibitors is present and is selected from the group     consisting of pyriproxyfen and methoprene, preferably pyriproxyfen. -   Item 6. The composition according to any one of the preceding items,     further comprising at least one additional solvent selected from the     group of cyclic carbonates, such as preferably propylene carbonate,     and/or at least one additional solvent selected from the group of     aromatic alcohols, such as preferably benzyl alcohol. -   Item 7. The composition according to item 6, comprising at least one     cyclic carbonate, such as preferably propylene carbonate, and at     least one aromatic alcohol, such as preferably benzyl alcohol, in a     ratio of about 1:5 to 5:1, preferably about 1:4 to 4:1, more     preferably about 5:1, more preferably about 4:1. -   Item 8. The composition according to item 6 or 7, wherein benzyl     alcohol is present in an amount of ≤about 20.0 wt. %, preferably     ≤about 15.0 wt. %, more preferably ≤about 10.0 wt. %. -   Item 9. The composition according to any one of the preceding items,     comprising ≤about 50.0 wt.-%, preferably ≤about 40.0 wt.-% of the at     least one aliphatic cyclic carbonate, such as preferably propylene     carbonate. -   Item 10. The composition according to any one of the preceding     items, wherein at least one crystallization inhibitor and/or     solubilizer is present, preferably one selected from the group     consisting of sorbitan monolaurate (Span 20), glycerine, propylene     glycol and from one or more vegetable oils. -   Item 11. The composition according to any one of the preceding     items, which is in the form of a spot-on formulation or a pour-on     formulation. -   Item 12. The composition according to any one of the preceding items     for use in the prophylactic or acute treatment of animals against     ectoparasites, in particular against lice, ticks, fleas, mosquitos     and sand flies. -   Item 13. The composition according to any one of the preceding items     for use in the prophylactic or acute treatment of hobby animals,     pets, laboratory and test animals, such as preferably mice, rats,     guinea pigs, golden hamsters, dogs and ferrets and hedgehogs, more     preferably dogs and ferrets. -   Item 14. The use of carvacrol as a solvent for dissolving an active     ingredient combination as defined in any one of the preceding items,     in particular in a composition as defined in any one of the     preceding items. -   Item 15. A method of controlling ectoparasites on animals, the     method comprising topically applying a composition as defined in any     one of the preceding items to an animal to be treated. 

1-15. (canceled) 16: A composition for the control of parasites on animals, comprising at least one active substance selected from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids); at least one active substance, selected from the group of pyrethroids; and ≥8.0 wt.-%, based on the weight of the total composition, of carvacrol as a solvent. 17: The composition according to claim 16, wherein the active substance from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids) is imidacloprid, and the active substance from the group of the pyrethroids is permethrin. 18: The composition according to claim 16, wherein the solvent carvacrol is present in an amount of ≥10.0 wt.-% based on the weight of the total composition. 19: The composition according to claim 16, comprising: from about 2.5 to 12.5 wt.-% of at least one active substance selected from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids); and from about 30.0 to 60.0 wt.-% of at least one active substance selected from the group of pyrethroids; in each case based on the weight of the total composition. 20: The composition according to claim 16, comprising: from about 5.0 to 10.0 wt.-% of at least one active substance selected from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids); and from about 43.0 to 60.0 wt.-% of at least one active substance selected from the group of pyrethroids; in each case based on the weight of the total composition. 21: The composition according to claim 16, comprising: from about 6.5 to 10.0 wt.-% of at least one active substance selected from the group of agonists of the nicotinergic acetylcholine receptors of insects (neonicotinoids); and from about 34.0 to 55.0 wt.-% of at least one active substance selected from the group of pyrethroids; in each case based on the weight of the total composition. 22: The composition according to claim 16, wherein the at least one additional active substance from the group of development inhibitors is present and is selected from the group consisting of pyriproxyfen and methoprene. 23: The composition according to claim 16, further comprising at least one additional solvent selected from the group consisting of cyclic carbonates and aromatic alcohols. 24: The composition according to claim 23, wherein a cyclic carbonate is present and comprises propylene carbonate, and wherein an aromatic alcohol is present, and comprises benzyl alcohol. 25: The composition according to claim 23, comprising at least one cyclic carbonate, and at least one aromatic alcohol in a weight ratio of about 1:5 to 5:1. 26: The composition according to claim 23, wherein the at least one aromatic alcohol comprises benzyl alcohol in an amount of less than about 20.0 wt.-%. 27: The composition according to claim 23, comprising less than about 50.0 wt.-% of the at least one aliphatic cyclic carbonate. 28: The composition according to claim 16, further comprising at least one if a crystallization inhibitor and a solubilizer. 29: The composition according to claim 16, wherein the at least one of a crystallization inhibitor and a solubilizer is at least one selected from sorbitan monolaurate, glycerine, propylene glycol and vegetable oils. 30: The composition according to claim 16, which is in the form of a spot-on formulation or a pour-on formulation. 31: A method of treating animals against ectoparasites comprising (a) prophylactically applying the composition according to claim 16 to an animal or (b) acutely applying the composition according to claim 16 to an animal. 32: The method according to claim 31, wherein an animal to be treated is selected from the group consisting of hobby animals, pets, laboratory and test animals. 33: The method according to claim 32, wherein the hobby animals, pets, laboratory and test animals include mice, rats, guinea pigs, golden hamsters, dogs, ferrets and hedgehogs. 34: A method of dissolving one or more active substances in the composition according to claim 16 comprising contacting said composition with carvacrol. 35: A method of controlling ectoparasites on animals, the method comprising topically applying a composition according to claim 16 to an animal to be treated. 